This application claims the benefit under 35 U.S.C. §119(a) of Korean Patent Application No. 2003-45386, filed on Jul. 4, 2003, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an electrophotographic printer. More particularly, the present invention relates to a waste toner transfer apparatus to transfer waste toner generated during a printing process to a waste toner storage container and an electrophotographic printer using the same.
2. Description of the Related Art
In an image forming process of an electrophotographic printer, when an exposure unit scans light corresponding to image information onto a photoreceptor charged to a predetermined electric potential, an electrostatic latent image is formed on the photoreceptor. A developing unit supplies toner to the electrostatic latent image to form a toner image. Generally, four developing units containing cyan, magenta, yellow, and black toners are needed for a color electrostatic latent printer. The toner image is transferred to a recording medium directly, or via an intermediate medium, from the photoreceptor. While the recording medium passes through a fusing unit, the toner image is fused on the recording medium by heat and pressure. As a result of the above processes, a mono or color image is printed on the recording medium.
While a wet type electrophotographic printer uses a wet developer formed by dispersing toner powder in a liquid carrier, a dry type electrophotographic printer uses toner powder as a developer. In this case, waste toner remaining on a photoreceptor or on an intermediate transfer medium during the image forming process is removed therefrom and is collected in a storage container. The electrophotographic printer typically includes a waste toner transfer apparatus to transfer waste toner to the storage container.
FIG. 1 is a view illustrating a conventional waste toner transfer apparatus. Referring to FIG. 1, a cleaning apparatus 1 removes waste toner from a photoreceptor or an intermediate transfer medium (not shown). The waste toner removed by the cleaning apparatus 1 is transferred by a waste toner transfer apparatus 2 to a storage container (not shown). The waste toner enters a duct 4 through an inlet portion 3. A shaft 5 rotated by a drive motor 6 is installed in the duct 4 and a conveying coil 7 is coupled to an end portion of the shaft 5. The duct 4 and the storage container are connected by a pipe 8. The conveying coil 7 is installed to extend through the inside of the pipe 8. The waste toner entering the duct 4 through the inlet portion 3 is transferred by the conveying coil 7 to the storage container along the pipe 8. The inlet portion 3 is generally formed to be inclined downward from the cleaning apparatus 1 toward the duct 4 so that the waste toner can slide and enter the duct 4 by gravity.
In the waste toner transfer apparatus 2 configured as above, although the waste toner is supposed to slide down by gravity along the inclined inlet portion 3, waste toner particles sometimes coagulate into a waste toner lump due to an attraction force between the toner particles, and may adhere to an inner wall of the inlet portion 3, especially the lower wall. When absorbing moisture in the air, the waste toner lump is further increased so that the inlet portion 3 is narrowed or clogged. When the inlet portion 3 is narrowed or clogged, waste toner accumulates in the cleaning apparatus 1. Accordingly, the accumulated waste toner in the cleaning apparatus 1 may further harden in time. In this case, the waste toner may exert a load on the transfer unit 9 installed in the cleaning apparatus 1 to transfer the waste toner toward the inlet portion 3 so that the transfer unit 9 may be damaged. Further, the waste toner in the cleaning apparatus 1 exposed to the outside may contaminate the electrophotographic printer.